Recording system



C- A. HEILAND RECORDING SYSTEM Jan. 1, 1952 10 Sheets-Sheet 2 Filed Aug.11, 1944 1952 c. A. HEILAND RECORDING SYSTEM ,BY M 4 1 I /7 orr gs.

Jan. 1, 1952 HEILAND 2,580,427

RECORDING SYSTEM Filed Aug. 11, 1944 10 Sheets-Sheet 5 Jan. 1, 1952 c,HElLAND 2,580,427

RECORDING SYSTEM Filed Aug. 11, 1944 10 Sheets-Sheet 7 f" .11. as 79 Z02jiwenz oz CarZAJieiZand Jan. 1, 1952 g, HElLAND 2,580,427

RECORDING SYSTEM Filed Aug. 11, 1944 10 Sheets-Sheet 8 Ill 85 Jan. 1,1952 3, HEiLAND 2,580,427

RECORDING SYSTEM Filed Aug. 11, 1944 10 Sheets-Sheet 9 frzven/or cqg lA.He L'Zczn o c. A. HEILAND 2,580,427

RECORDING SYSTEM 10 Sheets-Sheet 10 Jan, 1, 1952 Filed Aug. 11, 1944 IIn uerzior Ce glA Hei [and fflorize s.

Patented Jan. 1, 1952 RECORDING SYSTEM Carl A. Heiland, Denver, Colo.,assignor to Heiland Research Corporation, Denver, 0010., a corporationof Colorado Application August 11, 1944, Serial No. 549,104

17 Claims. (Cl. 346108) This invention relates to an improved method andapparatus in which electrical and photographic devices are employed forgiving an immediately visible record of electrical or other phenomenawhich fluctuate with lapse of time, and the purpose of the invention isto provide an improved recording system which may be employed toindicate immediately and permanently fluctuations in values of anyphysical, chemical or electrical phenomena of either high or lowfrequency which may be indicated by the oscillations oi an electriccurrent.

' An electrical measuring and recording system 01 the typeto which thepresent invention relates may have, a wide variety of uses in the fieldsof science and industry, such as the measurement oilength'of time, thedetermination of temperatures by electrical resistance thermocouples,the indication and measurement of light by the use of photoelectriccells, the measurement of sound which is converted into electricalimpulses by a microphone, the measurement of magnetic forces through theagency of electric currents, the investigation oi mechanical strains andvibrations through the use of electrical strain gauges and vibrationdetectors, the measurement of the acidity of chemical solutions, forrecording the action of the heart and the brain in the field ofmedicine, and for various other uses in a field which has rapidly beenbroadened by the development of the science of electronics, in all ofwhich an understanding of the phenomena under investigation may beenhanced by a study 01' the variations in the action of the subjectunder investigation with lapse of time.

Heretofore, various forms of apparatus have been employed for providingpermanent records of time-variations of various phenomena beinginvestigated, but most of these devices, commonly termed oscillographsor recorders, have not been adapted for many purposes because oflimitations which have been inherent in their construction and oranization. In one type of recorder, the record has been made by moving apen or stylus which is responsive to the fluctuations in an electriccurrent and which moves over the record sheet, ma"ing an imprint of itsposition continuously or at intervals either by passing a high tensionelectric park at intervals through the pen point and t rou h achemically treated paper or by applyin ink through the point of t e penor stylus. In another class of oscillographs employing galvanometersprovided with mirrors, the movements of the mirrors which are responsiveto fluctuations in an electric circuit are caused to direct beams oflight onto a moving film contained in a camera, and a continuous recordof the current fluctuations has thus been made, but such a record isonly visible to the eye of the observer after the development of thefilm. Thus, while means have heretofore been provided for makingpermanent records of oscillations in an electric circuit which may beindicative of changes in various phenomena being studied, these deviceshave had the disadvantage that, where a pen point or stylus is employed,the apparatus is adapted for use only in the study of low frequencyphenomena, since the pen or stylus, because of its inertia, cannot bemade responsive to quickly changing fluctuations, while, in the otherclass of recording devices heretofore known, where a photographic filmhas been used, the recording method has had the disadvantage that therecord made by photographic means is not immediately visible butrequires the development of the film before the character of theoscillations can be known.

The principal object of the present invention is to overcome the defectsof both types of recording instruments heretofore used by providing arecording electrical instrument in which the pen arm or stylus is a beamof invisible radiation, having no inertia, and capable of producing upona traveling sheet a permanent and immediately visible record of thephenomena being studied. In carrying out this method of measurement andrecording, a beam of invisible radiation proceeding from a suitablesource is caused to be reflected by a mirror which moves with thearmature of a galvanometer in response to fiuc tuations in an electriccircuit which are indicative of changes in the phenomena underinvestigation, and this invisible ray is directed from the mirror of thegalvanometer to the surface of a traveling film which is so sensitizedthat it is responsive to the invisible rays proceeding from thegalvanometer mirror but not responsive to light rays which enable thefilm to be viewed by an observer through a filtering medium, whereby apermanent record is made on the traveling film and this record is madeimmediately visible to the observer.

In order to obtain these results, the invention comprises means forobtaining a correlated spectral discrimination for the invisibleradiations which are employed to produce the record, for the sensitizedpaper or film on which the record is made and for the radiations orlight rays under which the record is viewed by the observer. To producethe record, a radiation is employed which results in a trace being madewith the minimum expenditure of energy which corresponds in wave lengthto the spectral sensitivity of the film or paper; it is necessary thatthis radiation be not one which is contained in the radiation or lightwhich is employed for permitting the inspection of the record. To havethe proper spectral response, the film or paper must react readily tothe radiation which is employed for producing the record and must notreact to the radiation or light which is used for the observation of therecord and which must comprise a spectral band not containing the recordproducing wave lengths nor wave lengths to which the paper or film issensitive. Accordingly, by providing invisible radiations, sensitizedfilms and rays of light for inspection purposes which are mutuallydiscriminatory in their efiect, it is possible to make a record of highfrequency phenomena which is immediately visible without the film beingaffected in any way by the light under which the record is viewed.

In order to obtain this discrimination in the use of the differentagencies involved, it has been found desirable to use a record producingor primary radiation which is wholly or primarily or an invisiblenature, such as ultra-violet radiations or infra-red radiations, eitherseparately or almultaneously, although it is now the preferred practiceto use either form of radiation separately. Radiators and filters havingthe desired characteristics for producing either ultra-violet orinfra-red radiations and for permitting the inspection of the record onthe film while screening out the invisible radiations are well known andmay be adapted to the purpose of the present invention with slightmodifications. For producing ultra-violet radiations, a mercury vaportube may be used, while, to produce the infrared radiations, a tube witha carbon or metal filament may be employed. The color-temperature ofsuch radiations is lower than that generally used to produce visiblelight and the omission band of both the ultra-violet and the infraredradiations may be narrowed, if desired, by the use of appropriatefilters.

The emulsions for coating the paper or film upon which an immediatelyvisible record is to made are not available in the market and must bespecially prepared according to the present invention. Their preparationrequires sensitization to produce an immediately visible record and toproduce a maximum response to the invisible rays. Methods are now knownfor effecting the proper spectral sensitization of the film to produceresponse to the invisible rays. For example, sensitization for theinfra-red rays has been satisfactorily carried out by treating theemulsion with cyanine dyes such as neo-cyanine and xeno-cyanine dyes, orwith poly-canbocyanine dyes, including tetra-carbocyanine andpenta-carbocyanine. The sensitization of the film for response to theultra-violet rays may be effected in any one of several ways which arenow well known.

Thus, so far as the preparation of the emulsion is concerned, theprimary problem has been 'to provide an emulsion which will reactimmediately to the ultra-violet or infra-red radiations to produce apermanent record which is immediately visible. It has been found thatemulsions of high sensitivity having this characteristic of immediatevisible reaction to the invis== ible rays may be prepared by a two-stepprocess consisting in preparing first a bromide emulsion in thecustomary manner by causing a reaction between silver nitrate andpotassium bromid in the presence of colloidal gelatin and then coatingthe paper or film with this liquid, and then treating the emulsion onthe film or paper with a solution of silver nitrate of low concentrationor with two solutions, the first consisting of potassium nitrate of lowconcentration, and the second consisting of silver nitrate of lowconcentration which is applied after the emulsion has dried.

Depending upon the speed of travel of the film, the paper or film thustreated will be available for inspection in daylight under the filterswhich are used for inspection purposes and will continue to be visible.The speed of travel may be several inches per minute or several inchesper hour, depending upon the character oi! the phenomena underinvestigation. After the record has been made in the recordingapparatus, it may be coiled up in a roll and preserved ior future useand may be later inspected under subdued artificial light, or the recordroll may be fixed in the customary manner by a solution of sodiumthiosulphate after which it may be exposed to bright daylight withoutdanger of discoloration.

These and other objects and characteristics of the invention will appearmore fully hereinai'ter and the nature of the invention will beunderstood from the following specification taken with the accompanyingdrawings in which one embodiment of the apparatus for the presentinvention, which is capable of carrying out the improved recordingmethod hereinabove referred to, is illustrated. In the drawings,

Figure 1 shows an end elevation of the recording apparatus of thepresent invention with its principal parts enclosed in a cabinet orcasing, portions thereof being broken away and parts of the cabinetbeing illustrated by dotted lines in their open positions;

Fig. 2 shows a front elevation of the recording apparatus illustrated inFig. 1;

Fig. 3 shows a top plan view of the apparatus illustrated in Figs. 1 and2 with the top cover in its closed position;

Fig. 4 shows a vertical sectional view taken on the line 4-6 of Fig. 3:

Fig. 5 shows a vertical sectional view taken on the line 5-5 oi! Fig. 4;

Fig. 6 shows a vertical section taken on the line 6-6 0! Fig. 5;

Fig. 7 shows a horizontal section line lll of Fig. 4;

Fig. 8 shows a vertical section taken on the line 8--8 of Fig. i;

Fig. 9 shows a vertical sectional view taken on the line 9--9 of Fig.4.;

Fig. 10 shows a horizontal sectional view taken on the line i0l@ of Fig.9;

Fig. 11 shows a vertical section taken on the line il--M of Fig. 6;

Fig. 11 is a sectional view taken on the line ii -H of Fig. 11;

Fig. 12 shows an enlarged vertical section through one end portion ofthe receiving mirror assembly illustrated in Fig. 6, showing the meansfor eflecting the vertical and angular adjustment thereoi;

Fig. 13 shows an enlarged vertical section through an end portion of theprojection mirror illustrated in the upper left-hand part of Fig. 6 andassociated parts of the apparatus, illustaken on the trating the meansfor adjusting the normal an ular position of this mirror;

Fig. 14 is an enlarged vertical section taken on the line i4-l4 of Fig.6. illustrating the construction of the magnet and armature of one ofthe galvanometers;

Fig. 15 is a perspective view of one of the side plates of one of thegalvanometers;

Fig. 16 is a perspective view of the other side plate of one of thegalvanometers;

Fig. 17 is a perspective view of the principal parts of the group ofgalvanometers which are embodied in the recording apparatus,illustrating the means for operating the shutter by which the lightadmitted to the galvanometer mirrors is regulated, and showing, also,the means for operating a mirror by which time lines are recordedperiodically on the moving sheet or film; and

Fig. 18 is a chart showing the actions of different sources of invisibleradiations, sensitizing emulsions and observation filters as functionsof wave lengths.

Before proceeding to a detailed description of the recording apparatusillustrated in the drawings, reference will be made to the moreimportant parts of the construction and to the general mode of operationof the apparatus in order to facilitate an understanding of the detailssubsequently described.

Referring particularly to Fig. 6, it will be seen that the apparatuscomprises a portable case or housing having mounted in the upper partthereof an auxiliary casing 26 containing the source of invisibleradiations which, in this instance, is illustrated as a bulb 21 adaptedto be connected in an electric circuit and embodying a tube 28 adaptedto emit the invisible radiations which may be ultra-violet rays orinfra-red rays, or combinations of these, depending upon the characterof the bulb which is used. These rays pass downwardly through a slot 2"in the bottom of the auxiliary casing I along a line 29 and impinge uponthe concave surface of a cylindrical projection mirror 34, which is sodescribed because it is constructed as an arcuate segment of a completecylinder. This mirror is adjustable angularly and the invisible rayspass from its surface along a line II to concave surfaces of cylindricalgalvanometer mirrors 3! which are mounted to oscillate with the movableelements of a series of galvanometers 33. These galvanometers arearranged side by side and each one is connected by a cable with a sourceof electrical oscillations to be studied with the use of the recordingapparatus. The mirrors 4! of these galvanometers oscillate aboutvertical axes in response to the oscillations in the respective circuitsto which they are connected'and the beam of invisible radiation 36 whichpasses from each galvanometer mirror 32 is thus caused to oscillate asit passes to a receiving mirror 31 which is constructed as a segment ofa cylinder and which is so mounted that its concave surface reflects theinvisible beam received along the line 36 downwardly along the line 30,through an opening 3! in a shield or apron 39, to the sensitized film orpaper 40 upon which the permanent record is made. A part of theinvisible rays reflected from the galvanometer mirrors 32 passes betweenthe mirrors I0 and I1, along the line 4| and impinges upon the surfaceof a frosted glass fluorescent screen 34, resulting in a brightlyilluminated line on that screen which indicates the fluctuations of thegalvanometer mirror to the observer through a slot I! formed in theapron 6 30 and positioned opposite the filter screen 42 forming asubstantial part of the front wall of the caseor housing 25.

This filter 42, which is constructed to exclude the invisible radiationsfrom the daylight, serves as the means for permitting the operator toview the permanent record which is formed on the sensitized film orpaper 40 by the oscillating beam 30 directed thereto from the receivingmirror 31. The sensitization of the film or paper being such that apermanent record is immediately made, this record may be viewed as thefilm 40 passes downwardly in the direction of the arrow 43 in front of aguiding plate 44. The records of the oscillations or fluctuations of theseveral circuits connected to the galvanometers 33 are indicated by thezigzag or irregular lines on the film or paper 40 in Figs. 2 and 4. Thefilm or paper is continuously supplied from a magazine 45 containing adrum or reel 45 upon which the sensitized paper is wound and, afterpassing over the guide plate 44 and a feeding roller 41, the film orpaper passes to a receiving magazine 48 containing a drum or reel 49 onwhich the exposed film or paper is continuously wound during theoperation of the apparatus.

The film or paper 40 is unwound from the drum 46 and wound upon the drum49 by the operation of a driving connection extending from an electricmotor 50 which is connected through change speed mechanism 5| and acoupling 52, shown in Fig. 4, with gearing mechanism which is capable ofadjustment to change the speed of movement of the film and which drivesa sprocket gear 56 connected by a sprocket chain 51 with anothersprocket gear 58 adapted to drive the drum 49 and a sprocket gear 59which is fixed on the shaft of the feed roller 41. In this way, themechanism of the recording camera may be con- .tinuously operated duringthe connection of the cables with the sources of oscillations beingstudied, and the beams of invisible radiations reflected by the severalgalvanometer mirrors 32 will be directed by the mirror 31 to thesensitized film or paper which will make an immediate record of theoscillations of the movable element of each galvanometer, these recordsextending parallel to each other on the paper sheet and being visible tothe observer as they pass downwardly over the guide plate 44.

With this preliminary explanation of the general features of operationof the apparatus, reference will now be made to the more detailedconstruction of its various parts. As shown particularly in Figs. 1, 2,3, 4, 5 and 6, the portable case or housing 25 comprises a base plate 60provided on its under side with legs or cushions SI of rubber or thelike which are adapted to rest upon the surface of a table or othersupport 62. Extending upwardly from the bottom plate 60 is a back plate63 which is united at its edges with the side plates 64 and 65, thelatter of which is removable in order to permit access to certain partsof the apparatus within the casing when desired. Spaced inwardly fromthe side plate 65 is an intermediate supporting plate 68 which isrigidly connected to the fixed side plate 64 by a number of cross framemembers 61, 68, 69, 10, H and 12, these parts forming a rigid framestructure which carries the principal parts of the apparatus, ashereinafter more fully described.

The front wall of the casing 25 is made up of a hinged wall or door 15which carries the filter 42 previously referred to. This door is hinged7| at 18 on the forward edge of the base plate 60 and normally occupiesan upright position which locates the filter 42 in front of and parallelto the guide plate 44 over which the film passes. The top edge of thedoor is arranged to overlap a transverse frame member 11 which extendsbetween the side plate members 88 and 65 and which serves as a supportfor a hinge '58 which provides a hinged mounting for the front edge ofthe auxiliary casing 26 containing the source of invisible radiations.When this auxiliary casing is in its normal position shown in Fig. 6,its upper side is closed by the top cover 89 of the casing which ishinged at 80 on the back plate 63 and which is provided at its forwardedge with a lip l9 overlapping the upper edge of the forward wall of thecasing 26. The portable casing is adapted to be transported through theagency of a handle 8i which is connected at one end to a bracket 82fixed to the top part of the side plate 64 and which carries at itsother end a ring 83 adapted to form a detachable engagement with a snaphook 84 secured to the top edge of the side plate 65. When the handle 8|i disengaged from the hook 84, the top cover l9may be swung upwardly topermit access to the contents of the casing and in particular to thecontents of the auxiliary casing 25. When the cover 19 has thus beenraised, the auxiliary casing 20, containing the source of invisibleradiations, may be swung upwardly about its hinge 78 to permit moreready access to the bulb 2i and its connections and to the parts of theapparatus which are positioned below the normal position of the casing26. t

The auxiliary casing 25 comprises a bottom plate 85 which contains theslot 26 previously referred to for permitting the passage of radiationsdownwardly from the bulb 2'! to the mirror and this bottom wall extendsthroughout a substantial part of the width of the casing, as shown inFig. 5. Side walls 88 extend upwardly from the sides of the bottom wall85 and these side walls are connected at their rear edges by the backwall 811 of the auxiliary casing. At their forward edges, the bottomwall as and the side walls 88 are connected by the from; wall 88 whichhas formed therein an aperture 88 through which the front end of thebulb 2?! projects. The bulb 21 is enclosed by a tubular envelope orshell 90 which is closed at its forward end and which extends rearwardlywith the bulb through the aperture 88 and also through an aperture 81formed in the rear wall 811 of the auxiliary casing. This shell isprovided on its under side with a slot 90 registering with the slot 25in the bottom wall 85 in order to permit the invisible radiations topass downwardly from the tube 28 to the mirror 30 and is adjustablysecured in position by set screws 89 engaging the members 81! and 88 sothat it may be rotated to cause these slots to register. The rear wall8'! has attached thereto a supporting ring 9! on which there is fixed,by brazing or the like, the forward end of a sleeve 92 closed at itsrear end by a disk 03. The shell 90 extends through the member 9! andwhen the set screws 89 are released the shell 90 and the bulb 21 may beremoved. The sleeve 92 houses the-socket 94 which is threadedly engagedby the stem portion of the bulb 21 and the terminals of this socket areconnected to conductors 95 which lead through a cable 86 to a source ofelectrical energy through which the bulb 21 is energized during theoperation of the apparatus. The cable 96 may lead through a notch in theupper edge of one of the side walls of the casing 25 so that, when thetop cover 19 is swung upwardly, the auxiliary casing 28 and itsconnections may be swung upwardly and forwardly about the hinge 78. Whenthe auxiliary casing is in its normal horizontal position, as shown inFigs. 4 and 6, it is supported by the transverse frame member ll and bythe transverse frame member 87.

For cooling purposes, a fan 91, driven by the motor 50, is arranged todischarge air through a conduit 98 which leads into the auxiliary casing26 through an aperture in the rear wall 81 positioned at one side of thesleeve 92 and the air which is thus introduced into the auxiliary casingfor the purpose of cooling the bulb 27 is discharged into the atmospherethrough openings 19 which are formed in the top cover 19 immediatelyabove the open upper side of the casing 26.

As illustrated in Figs. 6, l1 and 13, the projecting mirror 30 comprisesa mirror proper mounted upon a backing plate and this composite plate isprovided. at its ends with relatively fixed trunnions l00 which arejournaled in bearings formed in bearing plates l0! attached to the underside of the bottom wall of the auxiliary casing 26. One of the trunnionshas adjustably mounted thereon by means of a set screw I02 a laterallyprojecting arm I03 which extends between two lugs [M and I0! formed onthe adjacent hearing plate i0l. The lug llll i socketed to receive acoil spring I05 which engages the under side of the arm I03 and theupper side of this arm is engaged by an adjusting screw 505 having athreaded engagement with the lug l0| and with the bottom wall 85 of theauxiliary casing. This adjusting screw I05 is accessible through theauxiliary casing when the top cover 19 has been elevated for the purposeof adjusting the angular position of the arm I03 and the correspondingangular position of the mirror 30, which adjustment may be required inorder to cause the beam M of invisible radiations to impinge at theproper points upon the cylindrical mirrors 32 of the galvanometers 33.By the use of the set screw I02 for regulating the normal position ofthe arm H03 on its trunnion I00, a wide range of adjustability may thusbe obtained.

The receiving mirror 31 is also adjustably mounted, as shownparticularly in Figs. 4, 6, l1 and 12, and it is also capable ofadjustment vertically in order to vary its spaced relation to the filmor paper 40. For this purpose, the mirror 37 and its backing plate areprovided with longitudinally extending trunnions l06 which are journaledin bearing plates I07 and which slidably engage elongated slots i08formed in supporting plates I08 mounted on the bottom wall 85 of theauxiliary casing and constituting the end walls of the apron or shield39, previously referred to, which encloses the mirrors 30 and 311 excepton the inner sides thereof which are directed toward the galvanometermirrors 32. These end plates I08 are shaped to conform to theconfiguration of the apron 39 and the bottom wall 39 of the apron, whichhas the slot 30 formed therein, is extended rearwardly beyond the endplates I08, as shown in Figs. 6- and 12, in order to protect thesensitized film or paper 40 from all light rays or other rays except theinvisible radiations which pass thereto through the slot 39*. The endplates I08 are also provided with elongated slots I08 located invertical alignment with the slots I08 and arranged to be engaged by pinsH0 which extend from the upper portions'of the plates 1 01. The upperparts of the plates I01 are provided with lugs I01 which are threadedlyengaged by adjusting screws III which extend upwardly through the bottomplate 85 of the auxiliary casing, being provided above this wall withheads II I adapted to be engaged by a screw driver for regulating theelevation of the plates I01 with respect to the supporting plates I08,thereby varying the spaced relation of the mirror 31 and the portion ofthe film or paper 40 which is located beneath the slot 38. Collars IIIhold the screws III against endwise movement withrespect to the plate85.

One end of the mirror 31 is provided with a rearwardly extending arm H2which is provided with an aperture loosely engaged by the lowerunthreaded portion of an adjusting screw H3 which extends upwardly andthreadedly engages an aperture in a lug Il carried by the adjacent plateI01. The upper threaded end of this adjusting screw extends through anaperture 85 in the bottom wall 85 of the auxiliary casingand the notchedend of this screw may be engaged by a screw driver for regulating itsposition in the lug I01 A coil spring H4 is mounted around the lower endof the adjusting screw between the lug I01 and the end of the arm H2 andnormally serves to'maintain the arm H2 against the head H3 of the screwso that, when the screw is adjusted in the lug I01", the angularposition of the mirror 31 is varied in order to cause the beam 38 ofinvisible radiations to pass properly through the aperture 39 in theshield 38.

As shown in Figs. 9, and 17, the galvanometers 33 which include therecording mirrors 32 are arranged in a group in parallel relationship atthe rear of the cabinet where they are supported by a pair of parallelbrackets I I5 secured to the back plate 83 and extending horizontallytherefrom. These galvanometers are capable of use apart from the presentinvention and are claimed in a copending application Serial No.

549,105, filed August 11, 1944,.now Patent No. 2,535,065, issuedDecember 26, 1950. In the embodiment illustrated, there are sixidentical galvanometers supported by and between these brackets, thisbeing a convenient number for the simultaneous study and recording of anumber of electrical phenomena. The galvanometers are so constructedthat their dimensions are comparatively small measured transversely tothe plane of incidence of the invisible rays, that is, the planedetermined by the lines ill and 38 for each galvanometer. The magneticfields of adjacent galvanometers are parallel to each other and parallelto or coincident with the planes of incidence and the coils of themovable elements of the galvanometers also occupy these planes ofincidence with the mirrors 32 mounted at right angles to those planes.To accomplish this arrangement. each galvanometer 33 includes apermanent magnet H6 having attached to its opposite arms two pole piecesH1 which, in effect, form continuations thereof. These pole pieces areprovided with opposite pole faces III, the dimensions of which are verylimited, measured transversely to the plane of incidence, as shown inFig. .14, this result being accomplished by tapering the magnetizablematerial of these pole pieces on opposite sides of each pole face, asindicated at II 1, the two surfaces II'I of each pole piece making anangle of about 60 degrees with each other. The magnet H5 and the polepieces III of each galvanometer are mounted between a pair of sideplates H8 and H8 which have the form shown particularly in Figs. 15 and16, respectively, and a stationary field piece or armature core I20 ismounted between the pole faces H1. The method of assembly of these partsis shown particularly in Figs. 6, 14, 15 and 16. The magnet H8 and thepole pieces II! are first placed against the lower part H8 of the plateI I8, which is shaped to conform to the contour ofthese members, andsecured thereto by screws I2I. The stationary field piece or armaturecore I20 is attached to the side plate H8 by means of a magneticallyinsulating spacing block I22 which is attached to the plate H8 andengaged by screws I23 which pass through the identical complementaryparts I20 of the field member I20. The complementary members I20 areprovided with vertically extending recesses which form a verticalchannel I20 of rectangular cross section which is adapted to receive atubular member I24, fc rmed of aluminum or the like and-mounted upon thesuspended shaft or ribbon I25 formed of gold alloy or the like whichcarries the movable coil I2'I of the galvanometer. The parts I20 of thefield piece I20 are tapered along their vertical edges I20 so that theirvertical faces are of the same width as the pole faces I I'l from whichthey are spaced by air gaps I28. After the field piece I20 has beenmounted on the block I22 to form the air gaps I28 of equal dimensions,and after the coil I21 has been assembled and placed in its properposition as hereinafter described, the magnet H6 is put in place againstthe bottom faces of the pole pieces H1 and the side plate I I9 of thegalvanometer is attached by screws I26 or the like to the field piecesIII, with the fiange II9 of this plate extending below and supportingthe magnet, thus forming a unitary structure.

In the assembly and mounting of the armature, cross bars I28 are securedto the upper and lower portions of the tube I24 to extend parallel toeach other and form a frame for the armature coil I21 which is formed bywinding relatively small insulated copper wire I30, such as gauge 45copper wire insulated with Bakelite enamel, about the cross bars. Aftermounting the mirror- 32 on the upper end of the tube I24, the ribbon I25is threaded through the tube and the coil is placed over the back memberI20 of the field piece with the tube I24 engaging the rear recess I20",this member I20 being then held by pins on the block I22 which is brazedorotherwise secured to the side plate H8. Thereupon, the

upper and lower ends of the ribbon are secured by their clampingdevices, hereinafter described, and the tube I24 is adjusted verticallyto the proper position on the ribbon and then secured to the ribbon.After adjusting the ribbon laterally, as hereinafter described, toposition the coil properly in the air gaps and to position the tube inthe recess I20 the front member is put in place and the screws I23inserted to hold the field piece in position. This method ofconstruction locates the supports for the coil entirely outside of theair gaps I28 so that a maximum of space is allowed for the portions ofthe windings which extend through the gaps. The vertical stretches ofthe coil occupy positions midway of the gaps I28 and the coil I2! isthus free to oscillate about the axis of the ribbon I25, beinginfiuenced by the current, the torsion of the ribbon and the action ofthe magentic field.

The side plate H8 has an upwardly extend ing part of rectangular outlinewhich is provided along its front edge with a transversely exassess?tending flange II8 and along its rear edge with a transversely extendingflange lit, which flanges terminate at their upper ends in inturned lipsIIil having their outer surfaces lying flush with the upper end of thebody of the plate, thus forming a support for the upper mounting of theribbon as well as for the coil E21 and th mirror 32 which is mounted onthe upper end of the tube I24. The forward flange N8 of the plate H8 isprovided with a square opening II8 which provides a passage for the beam3I passing to the mirror 32 and for the reflected beam 36 passingtherefrom, as shown in Fig. 6. The lower part H9 of the side plate H9 isshaped to conform to the outline of the magnet H8 and the pole pieces H1and its upper rectangular extension II9 of the other side plate isadapted to flt against the outer margins of the flanges H8 and H8, thuscompleting the enclosure or housing in which the upper part of theribbon I25 and the mirror 32 are mounted. The plate H9 is provided atits bottom with a transverse flange II3 which underlies and supports themagnet H5.

The mounting of the ribbon I25 is illustrated particularly in Figs. 6, 9and 10, where the upper end of the ribbon is illustrated as beingsecured in a clamp. I3I mounted on the lower end of a shank I32 which iskeyed within a tubular metal torsion head I33. An insulating connectorblock I34 is seated upon an insulating plate I35, formed of Bakelite orthe like, and this block I34 has a vertical aperture in which there issecured a metallic bushing I31 arranged to flt over the torsion headI33. The plate I35, to which the torsion head I33 is secured, isprovided with elongated slots engaged by screws I35 which enter threadedholes in the lips I l8 formed on the upper end of the side plate I I3 sothat, by loosening the screws. the plate I35 and the parts mountedthereon may be shifted with respect to the plates 3 and H9. The lowerpart of the torsion head I33 is threaded to pass through an aperture inthe plate I 35 and the lower end thereof is engaged by a nut I38, thusclamping the torsion head frictionally in position. The upper end of theshank I32 is threaded for engagement by an elongated nut I33 which isnotched at its upper end for engagement by a screw driver or the likeand which has an annular flange I33 rotatably engaging an annular grooveI33 in the torsion head so that upon rotation of the nut I39 there iseffected an endwise movement of the shank I32 which is splined to thetorsion head I33, thereby regulating the tension of the ribbon I25. Thenotches I33 in the upper end of the torsion head I33 may be engaged by aspanner wrench or the like and the entire torsion head may be thusrotated, against the frictional resistance exerted by the clamping nutI38, to carry with it the ribbon I25 and thereby adjust the position ofthe mirror 32 so that the beam 3i received thereby will be properlydirected along the line 36 to the mirror 31.

At its bottom end, the ribbon i225 is secured in a clamp I42 fixed on aninsulating plate I43 which is provided with elongated slots engaged byscrews I44 by which the plate is clamped to the side plate II8 of thegalvanometer at a point slightly above the lower part of the magnet iii.By loosening the screws I 36 and the screws i44, both 01' the insulatingplates H85 and M3 may be adjusted simultaneously on their supports tocause the vertical portions of the coil it'i to i2 occupy the properpositions within the air gaps 828.

One end portion of the wire which forms the winding of each galvanometercoil is extended loosely to an insulated terminal post I45 mounted onthe flange II8 of the side plate III, as shown in Fig. 6. The outer partof this terminal member is slotted for engagement by the bifurcatedlower end of a metal clip I48 which extends upwardly and is secured by aterminal screw I41 to one end of the insulating connector block I34where it is attached to one wire 35 of the supply cable 35 through whichelectrical oscillations to be studied and recorded are received. Theother wire 35 of this electrical connection is soldered to a flangeformed on the upper end of the metallic bushing I31, thus forming anelectrical connection through the torsion head I33 and the shank I32with the ribbon I25 to which the other end of the wire I3!) is solderedor otherwise secured in the region of the coil I21. The metal bushingI31 fixed in the connector block I34 fits over the torsion head I33 andthe entire block I34 and the parts carried thereby may be lifted out ofengagement with the torsion head and the terminal post I45 to disconnectthe supply conductors from the galvanometer.

The ribbon I25 is constructed as a comparatively narrow flat memberoccupying a" plane which is parallel to or coincident with the plane ofincidence of the beam coming to the mirror 32 so that the oscillation ofthe coil I21 sets up a torsional strain in the ribbon which tends toreturn it and the mirror to their normal positions. By adjusting thenuts I39 at the upper ends of the shanks I32, the tensions of theribbons I25 .0! the various galvanometers may be regulated in order toadjust the sensitivity of the galvanometers to the oscillations in theelectric current traveling through the coils I21. By adjusting thetorsion head I33 01' each galvanometer angularly on its supporting plateI35, the connected mirror 32 may be regulated in its position so thatthe beam 36 reflected therefrom will impinge upon the mirror 31 at theproper position laterally thereon.

In addition to the adjustments just mentioned, provision is made foradjusting the galvanometers bodily on their supporting brackets I I5about the center lines of the reflecting surfaces of their respectivemirrors 32, thus causing a vertical adjustment of the positions of thebeam 3.3 so that it will be reflected properly to the mirror 31. Themeans for effecting this angular adjustment of the galvanometers areshown particularly inFigs. 4, 6, 9, 15, 16 and 1'1. Mounted on' thesupporting brackets H5 at the front and rear sides of thegalvanometersare a pair of supporting bars III which are secured to the brackets withrubber blocks I5I interposed between the brackets and their under sidesto provide a somewhat resilient mounting for the galvanometers so thatthey will be less subject to external vibrations. These supporting barsI50 are provided with upwardly extending arcuate bearing surfaces I50which are concentric with the center lines of the cylindrical mirrors 32of the galvanometers, as illustrated particularly in Fig. 6. The sideplates H3 and N9 of each galvanometer are provided on their front andrear edges with projections III and H9, respectively, which have lowerbearing surfaces concentric with the surfaces I5Il, so that theseprojections may rest edgewise on the bars i5!) and permit angularadjustment of the field structure of the galvanometer and all otherparts thereof about the center line of the reflecting 13 surface of theassociated mirror 32. At each side of each galvanometer, an anglebracket I52 is secured to the pole piece II1 by a screw I53, thevertical flange of each bracket lying between two of the projections II8 and I I8 and the top flange thereof lying flush with the uppersurfaces of these projections. The top flange of each bracket isprovided with an elongated slot I52 through which extends a threadedstud I54 secured in the underlying bar I50. The upper ends of thesestuds are engaged by clamping nuts I55 which are slotted for engagementby a wrench or screw driver so that they may be adjusted to clamp thegalvanometer in position or release it so that it may be angularlyadjusted in the manner described. In this way, the several galvanometers33 may be independently adjusted on the supporting bars I50 in order tocause the beams 36 reflected therefrom to strike the mirror 31 in theproper locations.

. In the recording system herein described, means are provided, ashereinafter described, for changing the speed of movement of the film orpaper 40 and, in order that proper results may be obtained whenoperating at different speeds, apparatus has been provided inassociation with the galvanometers for cutting down the radiationsadmitted to the mirrors 32 when operating at low speeds and, inaddition, means have been provided for automatically marking thesensitized film or sheet with equally spaced time lines appropriate forthe speed at which the film is moving. The means for reducing the amountof invisible radiation admitted to and reflected from the galvanometermirrors 32 when operating at a low speed includes a shutter I60 whichnormally occupies a horizontal position, as shown in Fig. 6, and whichis adapted to be swung upwardly to the position shown by dotted lines inFig. 17. This'shutter is in the form of a thin flat plate having aplurality of square apertures I60 formed therein which are located sothat, when the shutter is in its upright position, each of the aperturesI60 will be located opposite one of the square apertures I I8 in thegalvanometer casing. The apertures I60 are substantially smaller thanthe apertures II8= so that, when the shutter is in its upright position,the invisible radiations passing to and reflected from each galvanometermirror 82 are substantially reduced, which is desirable in order toprevent overexposure of the film when moving at a low rate of speed.

The shutter I60 is mounted on a small shaft III whichhas one end securedto a piston I62 mounted to travel in a cylinder I63 in which there is acoil spring I64 tending normally to move the shaft and its shuttertoward the right, as viewed in Figs. 9, 10 and 17. The other end of theshaft I6I is secured to a plunger I65 which is slidably mounted in asleeve I66 at the right end of the apparatus, as viewed in Figs. 9, 10and 1'1. The sleeve I66 is provided with a helical slot I86 engaged by apin I61 which is fixed on the plunger I65. The cylinder I63 and thesleeve I66 are secured in apertures in two supporting plates I88 whichhave their lower ends pivotally mounted on screws I68 engaging thereadedapertures in the brackets I I by which the galvanometers are supported.The plates I68 normally occupy the elevated positions shown in Figs. 4,9 and 10, in which positions the rearward swinging of these members islimited by pins I10 fixed in the brackets I I5. The members I68 arenormally held in their upright positions by leaf springs I1I which aresecured to the under sides of the brackets II 5 with their free endspressing against flat surfaces I68 formed on the lower ends of themembers I68. When it is necessary to have access to the galvanometersfrom the front, the supporting plates I68 and the parts carried therebymay be swung downwardly and forwardly.

With the mounting of the shutter I60, it will be apparent that, uponpressing inwardly toward the left on the plunger I65, the inclined slotI66, coacting with the pin I61, willrotate the shaft I6I and thuselevate the shutter to its upright position. This movement is broughtabout automatically at the time of changing the speed of operation ofthe recorder, by a shoft I12 which extends vertically at one side of thegroup of galvanometers and which has mounted thereon a rearwardlyextending arm I13 positioned opposite the end of the plunger I65, asshown particularly in Fig. 17. This shaft I12 is provided near its lowerend with a rearwardly projecting arm I14 which is pivotally connected toa shift rod I15, through the operation of which the change from aminutely rate of recording, for example, to an hourly rate, is effected,as hereinafter set forth. When the shift rod I15 is actuated to changeto the slower rate of operation, the arm I13 on the shaft I12 is at thesame time moved toward the left, as viewed in the drawings, to move theshutter I60 to its upper position and thereby restrict the galvanometeropenings.

Theplates I68, which are pivotally mounted on the brackets II5, alsoserve to support a concave cylindrical mirror I11 which is fixed on ashaft I-18 journaled in the forward portions of the plates I68 in suchpositions that the mirror I11 occupies a position just below the lowermargins of the galvanometer openings H8 and in front of the shutter I60when the shutter is in its normal horizontal position, as shown in Figs.6 and 17. The shaft I18 is provided at the end adjacent the shaft I12with a crank arm I19 which is engaged by a leaf spring I60 attached tothe adjacent supporting plate I68 and adapted to turn the mirror I11 toa position where it will direct a part of the rays received from themirror 30 to the mirror 31. The crank arm I19 has a projecting part I18which lies in the path of movement of the end portion I8I of a triplever I8I of bell crank form which is pivoted by a pin I82 on a lowerpart of the shaft I12 so that the lever turns with the shaft. This triplever has a horizontal arm I8I terminating in a downwardly extendingfinger I8I which is adapted to be actuated at the end of each minutewhen the apparatus is operating at a minutely rate and at the end of thehour when the apparatus is operating on an hourly rate. With eachdownward movement of the arm I8I the crank arm I18 is released by theextremity I8I' of the lever which passes loosely through an aperture inthe upper part of the shaft I12 and the crank arm I19 is thereby rotatedby the spring I to cause the mirror I11 to reflect a part of the rayspassing from the mirror 30 directly to the mirror 31, indepently of thegalvanometer mirrors, so that an invisible radiation is thereby directedonto the surface of the film to form a horizontal time line. Havingdescribed the galvanometers and the parts immediately associatedtherewith, further reference will now be made to the camera mechanism,including the previously mentioned magazines 45 and 48 which are locatedbehind the guide plate 44 over which the film or paper 40 moves in thedirection of the arrow 43, these features being particularly shown inFigs. 4, 6

15 and 11. The magazine 45 is in the form of a cylindical shell closedat its inner end by an end wall 45 which has secured therein the innerend of the drum 46 upon which the supply of sensitized paper or firm iswound. This drum 46 has a sliding fit on a tube I85 which is fixed atits inner end in the intermediate supporting plate 66 of the case 25.When the magazine has been fully inserted, the drum 46, which is closedat its outer end by a disk 48*, extends beyond the outer end of the tubeI85 but term.nates short of the outer end of the cylindrical outer shellof the magazine. This end of the magazine extends into an opening 64formed in the side plate 64 of the case 25 and this end of the magazineis closed by a circular cover I86 which is recessed to give it acup-shaped form and which has a handle portion I86 extending across therecess. The cover I86 closely fits the outer end of the magazine and hasa flange I86 which extends over the end of the magazine wall to form alight-proof closure. The cover I86 is recessed on its inner side asshown at I86 to receive the extremity of the drum 46 and the cover isnormally secured in this position by a pair of latch members I81 whichare located diametrically opposite to each other and which are pivotallymounted on pins I88 within recesses which are formed in opposite sidesof the cover. The latch members have lugs I81 which engage holes in thewall of the magazine when the cover is fully inserted and these lugs arepressed into engagement with these holes by leaf springs which aresecured to the latch members, as shown in Figs. 11 and 11 The outer endsof the latch members are bent transversely as shown at I81 and bypressing inwardly upon these extensions of the latch members the covermay be released and then removed from the magazine by engaging thehandle portion I86. With this construction, the supply of new film orpaper may be put on the drum 46 when the magazine is removed from therecording apparatus, under conditions where the film will not beinjured, and the cover I88 may then be applied to the magazine and themagazine may be inserted bodily in the recording apparatus through theaperture 64 in the end wall thereof.

The cylindrical wall of the magazine 45 is provided with a longitudinalslot 45, extending substantially throughout the distance between the endwall 45 and the cover I88, through which the film 48 is withdrawn durinthe operation of the apparatus. A pair of fiat metal bars I89 aresecured to the magazine along the margins of the slot 45 and a sheet ofvelvet or the like is secured to the magazine under one of these barsand arranged normally to overlap the slot, thus excluding light duringthe withdrawal of the film. The end wall 64 of the case or housing 25 isprovided with a notch 84 along the margin of the aperture 64 to receivethe bars I89 when the magazine is inserted. When the magazine has beenpushed to its inner position on the tube I85, it is turned in acounterlockwise direction, as shown in Fig. 1, thereby moving one of thebars I89 to a position behind the end wall 64 so that the magazine isthereby held a ainst accidental removal. The limit of this movement isdetermined by the transverse frame member 68 against which the left-handbar I89 seats, as shown in Fig. 6. When the film in the magazine 45 hasbeen completely withdrawn, the magazine may be rotated in a clockwisedirection through the agency of the cover operation of the latch membersI81.

16 handle I86 to bring the bars I89 again into registry with the notch84*.

After emerging through the slot 45 in the upper magazine, the filmpasses over the upper horizontal portion of the guide plate 44 which ispositioned beneath the mirror 31 and it then travels around the curvedpart of the guide plate and downwardly in front of the vertical portionthereof, the guide plate being secured in stationary position on thetransverse frame members 68, 69 and H. From the lower end of the guideplate 44, the film passes into the magazine 48 which contains the drumupon which the exposed film is wound. This magazine has an end wall 48secured to its cylindrical wall and having a hub member I98 secured tothe central part thereof. Journaled in this hub member is a takeup shaftI9I having a squared extremity I9I which fits a square recess in theblock I92 secured in the outer end of the drum 49. This drum is providedat its inner end with a bearing ring I93 which is journaled on the hubmember I99 carried by the end wall of the magazine. In this way, thetakeup shaft is capable of being rotated, as hereinafter described torotate the drum 49 with respect to the magazine 48 for the purpose ofwinding-on the drum the exposed film or paper which is received from thefeed roller 41. For the purpose of forming a connection with the end ofthe film, the drum 49 is provided with an inclined slot 49', shown inFig. 6, engaged by the reversely bent end of the film or paper so thatthe film or paper is wound when the drum 49 is rotated in the directionof the arrow I94 through the actuation of the shaft I9 I as hereinafterdescribed. The outer end of the drum 49 is joumaled in a bearing ringI95 seated in a recess formed in the inner face of the cover I96 whichis similar in construction to the cover I88 previously described, beingrecessed on its outer face and provided with a transverse handle portionI96 through which it may be manipulated. This cover I96 is secured inplace within the outer end of the drum 48 by latch members I91 whichhave lugs I91 adapted to engage holes 48 formed in the drum on oppositesides thereof. The latch members I91 are pivoted on pins I98 located inrecesses in opposite sides of the cover and leaf springs I99 are securedto these latch members and engage the inner walls of the recesses toforce the lugs I91 into engagement with the holes 48' The transverselybent end portions I91 of the latch members may be engaged bythe fingersof the operator to permit them to be pressed inwardly to release thecover. The construction and operation of the latch members I91 are thesame as the construction and When the cover has been removed, theoperator may place the end of the film into engagement with the slot 49in the drum, preferably in semi-darkness, and then, after the coverhasbeen reinserted, the parts are in readiness for the winding ofthe film.

The drum 48 is provided on one side with a longitudinal bar 288, shownin Fig. 1, which is adapted to slide through a notch 84 formed in theend wall 64 at the margin of the hole I54 in the end wall which isengaged by the magazine when inserting it into the casing. After themagazine has been fully inserted, it is rotated slightly in acounterclockwise direction, thus bringing the bar 208 opposite the endwall 64 to retain the magazine in place. When the film has been rewound,a slight angular movement of the magazine through force applied to thehandle I96 will restore the bar 200 to a position registering with thenotch 64 so that the entire magazine may then be withdrawn with is coverattached, during which operation the drum 49 slides out over the takeupshaft l9! and the block I92 moves out of engagement with the square endof the shaft.

The film or paper 40 is held in contact with the feed roller 41 by anidler roller 20f which is rotatably mounted in a U-shaped roller frame202 pivoted at 203 on brackets 204 carried by the base plate 60, asillustrated in Fig. 6. A pair of leaf springs 205 are secured to thebase plate 60 and normally press the side arms of the roller frame 202upwardly so that the idler roller 20l is held with resilient pressureagainst the film or paper and a close frictional engagement of the filmor paper with the feed roller 41 is thereby obtained. The leaf springs205 engage a transverse member 206 of the roller frame and the upwardmovement ,of this frame is limited by the contact of the member 206 witha bar 201 of Z-shaped cross section attached to the base plate 60. Aguide plate 208 is mounted above the bar 201 and serves to guide thefilm or paper toward a slot 48 in the magazine.

From the feed roller 41, the film passes through the slot 48 in themagazine 48 and then engages the reversely inclined slot 49" in the drum49. A curved knife blade 2 I0 is mounted on the outside of the magazine48 and has a slot 210 having a cutting edge along one margin thereof andadapted to register with the slot 48. This knife blade is provided witharcuate slots which engage rivets 2H secured in the wall of the magazineand the knife blade is held against movement about the axis of rotationof the drum 49 by two stationary bars 2 l2 which have their ends securedin the plates 64 and 66. Assuming that a desired record has been madeand that the exposed part of the film or paper is to be removed whilecontained in the magazine, the magazine is first rotated to bring thebar 200 on its outer side into registry with the notch 64, shown inFig. 1. During this slight rotation of the magazine, the knife blade 2 i0 is held stationary by the bars 2l2 so that the cutting edge of theblade severs the film and at the same time these bars move the blade toa position where it closes the slot 48 in the magazine, therebyprotecting the exposed film or paper against the action of undesiredradiations when the magazine is withdrawn from the case. In addition tothe notch 64, the end wall is suitably notched as shown at 64 to permitthe endwise movement of the knife blade 2 [0 through the end wall 64when the magazine is removed.

As heretofore mentioned, the feed roller 41 and the drum 49 are drivenfrom the electric motor 50 through connections which include the speedchange mechanism 55. These driving connections are illustratedparticularly in Figs. 4, 6, 7 and 8, where the motor 50 is illustratedas being carried by a plate 2 l4 which in turn is fixed on a plate 2l5attached to the base plate 60 of the case through the agency of studs 2l6 and rubber blocks H1. The shaft 50 of the motor, at the end thereofopposite the blower 91, is connected to the speed reducer which isconnected through a flexible coupling 52 with the driving shaft 2l8which drives the gearing mechanism 55 and which operates at a very slowspeed, for example, two revolutions per minute. The shaft 2! isjournaled inbearings in the walls of the casing 2 I9 which houses thegearing mechanism 18 and it has helical gears 220 and 22l rotatablymounted thereon and spaced apart. These gears are provided on theiropposed faces with clutch teeth 220* and 22", respectively, which areadapted to be engaged by the teeth of a clutch member 223 which issplined on the shaft 2! between the helical gears. The helical gears 220and HI mesh with other helical gears 224 and 225, respectively, whichare fixed on an intermediate shaft 226 having its bearings mounted inthe walls of the casing 2l9. The helical gear 225 meshes with anotherhelical gear 221 secured upon another intermediate shaft 228 having itsbearings mounted in the opposite walls of the casing 2|9. The gear 221meshes with a helical gear 229 rotatably mounted on the output shaft 230which is also journaled in bearings carried by the walls of the casing2I9. Another helical gear 23l of larger diameter than the gear 229 isalso rotatably mounted upon the shaft 230 and these two gears haveopposed clutch teeth 229 and 23l' which are adapted to be engaged by theteeth of a clutch member 233 splined on the shaft .230 between these twogears.

The speed with which the output shaft 230 rotates may have fourdifferent values, depending upon the positions of the clutch members 223and 233. The clutch member 223 is adapted to be shifted on the shaft 2l8by a shifting arm 234 which is bifurcated at its lower end to engage theannular groove in the clutch member 223 and which is attached at itsupper end to a hollow shaft 235 journaled at one end in the end wall ofthe casing 2 l9 and at theother end in a fixed frame member 236 mountedwithin this casing. A crank arm 23'! is secured on the end of the shaft235 and may be held in neutral position or in either of its drivingpositions by a resiliently mounted pin 231- adapted to engage one of aseries of depressions 238 formed in the end wall 64 of the case orhousing, as shown in Fig. 1. The other clutch member 233 is similarlyactuated by a shift member 239 which is bifurcated at its lower end toengage the annular groove in the member 233 and which is attached at itsupper end to a shaft 240 journaled in the frame member 236 and having atelescoping engagement with the hollow shaft 235. A crank arm 24! issecured to the outer end of the shaft 240 and a resiliently mounted pin24l= carried by this crank arm is adapted to engage one of a series ofdepressions 242 formed in the end plate 64 of the case or housing forholding the clutch member 233 either in its neutral position or ineither one of its driving positions.

The intermediate output shaft 230, which is thuscapable of being drivenat four different speeds, depending upon the positions of the clutchmembers 223 and 233, is extended through the top wall of the casing 219and has fixed on the end thereof a spur gear 244. This gear meshes withan idler spur gear 245 journaled on a stud shaft 246 and arranged tomesh in turn with a spur gear 24'| fixed on a shaft 248 and meshing withanother spur gear 249 which is fixed on a shaft 250. The shaft 248 hasfixed thereon within the casing 219 a worm 251 which meshes with a wormgear 252 rotatably mounted on the horizontal roller driving shaft 253which is journaled in the frame member 236 and in the end wall of thecasing 2 I9 and fixed on the outer end thereof the previously describedsprocket gear 56 by which the sprocket chain 51 is driven. The shaft 250has fixed thereon within the easing 9 a worm 254 which meshes with aworm ope -1a? ing rod l which is slidably mounted in the walls of thecasings H9 and 25. The worm 25! and worm wheel 252 transmit motion on al to 1 ratio but the worm 254 andworm wheel 255 transmit motion on a 60to 1 ratio. Thus, the shaft 053, .when coupled to the worm 2", turns asmany times in a minute as it does in an hour when it is coupled to theworm 255.

The sprocket gear 55 on the roller driving shaft 253 drives the sprocketgears 58 and 59 and thus drives the feed roller 41 and the takeup shaftE90 by which the drum is rotated. The roller Al is fixed on a shaft 258journaled in the plate 56 and in a bearing member 259 secured to the bae plate 50 and the s rocket gear 59 is secured on one end of this shaft.The sprocket gear 58 which drives the shaft I!" is mounted on a shortshaft 260 joumaled'and secured against endwise displacement in a ballbearing unit 260'. The short shaft 260 has attached thereto threehelical spring fingers 262 which are attached at their inner ends to afiber disk 263 arranged to bear against the outer face of a metal disk26d secured to the end of the shaft i9i. This disk 2% is mounted torevolve in the recess of a bearing member 265 secured in theintermediate plate 63 of the housing 25 and the disk is retained inposition in its hearing by a retaining ring 266 which is secured to theface of the bearing member and overlaps the ed e of the disk. The ballbearing unit 28l is mounted in a bracket 2M secured to the intermediateframe member 66 and the sprocket gear 58 is positioned in ali nment withthe sprocket gears 56 and 59 so that. when the shaft 253 is driven bythe connection heretofore described, the shaft i9! is actuated to rotatethe drum 4!! and thereby wind up the exposed portion of the film 4'1.Since the last portion of this driving connection is effected by thefrictional contact of the fiber disk 263 and the metal disk 264, it willbe apparent that slippage may occur and that the drum 49 will always bedriven at a sufficient s eed to wind up the film thereon regardless ofchanges in the diameter of the roll as it is wound.

is fixed on this shaft within the casing, as shown in Fig. 7. The worm213 drives a worm wheel 215 secured on a horizontal shaft 216 which isjournaled in bearings carried by the side wall of the gear casing andwhich has fixed on the outer end thereof a disk 21.1. The gear 2' has adepression 2" on its upper side into which the rounded end I8I of thetrip lever IBI is adapted to drop on each revolution of the gear whenthe apparatus is being operated on the minutely rate. When the shift rod"5 is operated to shift the clutch member 256 to change the speed fromthe minutely rate to the hourly rate, this shift rod operates at thesame time to turn the shaft I12 in its bearings and thereby turn the armI8l of the trip lever it! from the position where it drops into thedepression 21 i to a position where it drops into a depression fl!formed in the mar- As shown in Figs. 7 and 1'7, the shaft M8 which isdriven at a low speed by the motor 50 also serves to drive the mechanismby which the lever I8! is periodically operated to form time lines onthe film or paper 40 in the proper spaced relation, depending upon thespeed at which the camera mechanism is operating. For this purpose, theshaft 2 I 8, which rotates with a speed of 2 R. P. M., has fixed thereonabove the casing 2119 a pinion 268 which meshes with a gear 268 mountedto revolve on a short shaft 270 secured in the upper wall of the casingH9. The pinion and gear are of such relative sizes that the gear 269rotates with a speed of 1 R. P. M. and this speed is imparted by thatgear to a gear 2H of the same size which is fixed on the upper end of ashaft 212 Journaled in bearings carried by the upper and lower walls ofthe gear casing. A worm me gin of the disk 2'" during each revolution ofthis disk, the gear ratio of the worm 213 and the worm wheel 215 beingsuch that the gear 211' rotates 60 times as fast as the disk 2". In thisway, the trip lever I8! is operated either by the gear 2', or by thedisk 2", once during each revolution thereof, in order to actuate themirror ll'l through its crank arm H19 and thereby causing the invisiblerays to form periodic, equally spaced and immediately visible time linesupon the sensitized film or paper 40. The operation of this time linemechanism results in the production of time lines every minute or everyhour and is independent of the mechanism for changing the speed ofmovement of the paper or film.

The operation and advantages of the method and apparatus of the presentinvention will be apparent from the foregoing description, from which itappears that accurate, conveniently operated and efiicient means havebeen provided for studying oscillations representative of variousphenomena by making a permanent and immediately visible record throughthe agency of beams of invisible radiations which act as the "pen toproduce the trace on the sensitized paper, thus making the apparatusinstantly and accurately responsive to various types of oscillations,including those of higher frequency, since it is unneces ary to overcomethe inertia of any physical parts during the formation of the record. Byusingsensitizing emulsions which are responsive only to the invisibleradiations which are used to trace and record the oscillations of thecircuit or circuits under investigation and by employing an observationfilter which excludes the invisible record-making radiations, it ispossible to make a continuous permanent record for future study whilepermitting the observer to view the record progressively as it isproduced. These relations are illustrated in their quantitative aspectsin Fig. 18 of the drawing. In the upper row are two curves 280 and 28|showing by their ordinates the emissions of radiators in theultra-violet and infra-red regions, respectively, in relative unitswhich are percents of maximum emission. The abscissa of these curves arewave lengths measured in microns. The second set of curves show thespectral sensitivity of two types of emulsions, one curve 282 being foran emulsion which is sensitive to ultraviolet and blue and the othercurve 283 being for an emulsion which is sensitive to the infra-red. Theordinates of these two curves are on a logarithmic scale and representrelative sensitivities, or reciprocal inertias, in relative units ofergs per square centimeter. The third set of curves

